To measure pressure of a medium, such as a fluid, often a force gauge of known cross sectional area is exposed in some manner to the environment to be measured, thereby causing the force gauge to generate a signal. The generated signal, which corresponds to the actual force at the force gauge, is normalized to the sensor's active cross section, thereby providing a pressure reading.
Many types and shapes of pressure sensors have been designed over the years. FIGS. 1A-1C illustrate the three most common fluidic connections for pressure sensors. FIG. 1A shows a flow-through design that includes an inlet connection, a cavity and an outlet connection. Fluid flows into the sensing cavity via the inlet connection and then out of the sensing cavity via the outlet connection. FIG. 1B illustrates a dead-head or dead-end connection, where a sensor is connected via a single connection to the sensing environment. In the dead-head configuration, the forces within the sensing environment are transferred to the sensing cavity via the open association established by the connection tube. FIG. 1C illustrates an annular flow-through design, which uses an externally mounted strain gauge that measures deflection of a tube due to pressure variation. The sensing cavity of the annular flow-through design of FIG. 1C is fully swept by fluid.